A Moisture Resistant Air Cavity Plastic Microwave Power Package Capable of Eutectic Die Attach

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A Moisture Resistant Air Cavity Plastic
Microwave Power Package Capable of Eutectic Die
Attach
John W. Roman, Richard Ross, Tony Shaffer, Dave
Dewire RJR Polymers Inc., Oakland, California
510-638-5901
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RJR Polymers Inc.

• 
  Headquartered in Oakland, CA
• Worldwide sales and engineering force
• Manufacturer of injection molded plastic
  packages,
• pre-applied adhesives and equipment

Provider of engineered solutions to our
customers demanding product and process
applications. partners
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R-Pak Air Cavity Packages

• Plastic backed for low power package applications
  like sensors
• CCD / CMOS for vision and optical sensor
  applications with glass covers
• Thermally enhanced metal backed for microwave and
  power applications

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The R-Pak Process

• Packages are molded around leadframes in a
  multi-up format
• cost effective for molding and downstream
  assembly
• Plastic formulated to match the CTE of copper for
  low stress and reliability
• Leads are coated with moisture resistant polymer
  before injection molding
• RJR ITS equipment supports package assembly and
  sealing

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RJRs Injection Molded Packages

• Package Stackup
• Thermal Base (Cu, WCu, CuMoCu, AlSiC, etc)
• Sidewall with leads
• Lids with epoxy (pre-applied)
• RJR formulated epoxy as interstitial layers
• Plastic alloy formulated to match the CTE of
  Copper or Copper alloys (WCu, CuMo, etc.)
• Leads are coated with moisture resistant polymer,
  then injection molded
• The 3 layers are bonded together using RJR
  IsoThermal Sealing (ITS) equipment

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Thermally-Enhanced Package Build Process
Process Steps
RJR Polymers

• 1) Package Base

2) Leadframe with moisture barrier applied
3) Injection mold sidewall over leadframe
4) Nickel and Gold plate leadframe
5) Epoxy coat molded sidewall
Customer location or- RJR Location
6) Perform Die attach to base leadframe
7) Using RJRs ITS system attach assembled
base leadframe to coated injection molded
sidewall
8) Wire Bond device to package
9) Using RJRs ITS system seal package
lid to molded sidewall
10) Trim, Form and singulate
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• Thermally-Enhanced Package Exploded View

Package lid with pre-applied adhesive Lid
Material Plastic, Ceramic, Metal, Glass, etc.
Injection molded sidewall Shown with moisture
resistant seal encapsulating the leads and
pre-applied adhesive on bottom surface
Wire Bonds
Device
Solder Preform or Epoxy, etc.
Package Base Base Material Cu, Cu/Mo, Cu/Mo/Cu,
WCu, etc.
Completed Package
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Moisture Resistance

• IPC/JEDEC J-STD-202B Moisture/Reflow Sensitivity
  Classification for Nonhermetic Solid State
  Surface Mount Devices
• intended to classify nonhermetic solid state
  SMDs by moisture sensitivity to ensure that
  proper handling precautions are applied
• Applies to plastic SMDs with cavity or without
  cavity
• Basic issue is vapor pressure change of water
  during solder reflow cycle causing damage
• Delamination, cracking, leaks, popcorning
• Low moisture sensitivity comes from choice of
  materials, design of package and good processes

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Hermeticity

• JEDEC standard JES D22-A109-A defines test
  procedures
• Derivative of MIL-STD-883, Method 1013
• Historic military definition of hermetic means
  sealed to a specified helium leak rate
• Assumes cavity package
• Excludes organic seals or materials

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Nonhermetic and Near Hermetic

• Rationale that organics are non-hermetic based
  on diffusion rates of water through organic
  materials
• Metal, ceramic and glass are considered hermetic
• New organic materials challenge that definition
• Near Hermetic is a common term without a clear
  definition
• Moisture getters further confound the issue

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Package Elements to Consider

• Plus the process!
• Design
• Assembly

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Why Liquid Crystal Polymer?
Superex Polymer Inc.
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RJR Plastic Alloy HTP-1280

• R-Pak? Plastic Body Compound
• This custom thermoplastic compound is used in RJR
  R-Pak? plastic body package technology. The
  following properties are typical for the bulk
  material molded into standard test configurations
  defined by the applicable test method. These
  property values are intended for general
  engineering purposes and are not intended for
  establishing product specifications.
• Physical
• Density 1.67 gm/cc ASTM D792
• Water Absorption 0.02 ASTM D570
• Mechanical _at_ 23C
• Tensile Strength 21,000 PSI ASTM D638
• Tensile Modulus 2.5 X 106 PSI ASTM D638
• Elongation _at_ Break 1.2 ASTM D638
• Flexural Strength 31,000 PSI ASTM D790
• Flexural Modulus 2.4 X 106 PSI ASTM D790
• IZOD Impact Strength Notched 1.6 ftlb/in ASTM
  D256
• Thermal
• Melting Point 280?C (536?F) ASTM D3418
• DTUL _at_ 1.8 Mpa (264 PSI) 270?C (518?F) ASTM
  D648
• Electrical
• Volume Resistivity 1012 ohm-cm ASTM D257
• Surface Resistivity 1017 ohm IEC 93
• Dielectric Strength 766 V/mil ASTM D149

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Epoxy Sealing Materials

• Common properties
• Minimal moisture transmission
• Low ionics
• Very low volatiles (outgassing)
• Cure in minutes for efficient assembly
• Lead primer formulation
• Adherent to LCP and lead finish
• Viscosity supports efficient lead coating process
• Sealing epoxy
• Uniform cover and sidewall coating
• Easily B-staged

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Process

• Design
• Appropriate sidewall thickness
• Molding process
• Tool design and process control
• Epoxy application
• Complete 4 sided primer application
• Consistent application to sidewall and cover
• Package assembly process
• Isothermal Packaging System (ITS)
• Lead forming
• Tool design critical to maintaining package
  integrity

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Sealing Equipment - ITS (Isothermal Packaging
System)

• Semiautomatic
• Custom Designed and Built Plates
• Controls
• Time
• Pressure
• Temperature
• UPH 600 - 700
• 99 Yield

Run Rates are Dependant on Package Size and
Configuration
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Isothermal Packaging System

• Lid is held up during temperature ramp up
• At temperature, lid is released onto package
• Piston applies pressure to lid preventing
  pinholes and blowouts

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Thermally Enhanced R-Pak

• Moisture resistant and near hermetic
• Capable of eutectic die attach
• High thermal dissipation capability
• High frequency capability
• parts in service at 5.8 GHz
• Can pass JEDEC Level I Moisture Pre-Conditioning
• Pass Mil-Std 883 Section 1010 Condition C temp
  cycle

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RELIABILITY TESTING

• RESULT

• TEST

• CRITERIA

• SO2F

• SO8

• V32

• LD2

• V48

• V52

• THERMAL SHOCKJEDEC A106A, Condition C.15cycles,
  125C to -65C

• GROSS LEAKJEDEC A109, Condition C13

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• MOISTURE SENSITIVEJEDEC A112A /
  J-STD-20-A85C/85HR, 168hrs

• DIE PENETRATIONMIL-STD- 883E, Method 1034

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

INC
INC
INC

• INTERNAL VISUALMIL-STD-883E, Method 2014

• SOLDER REFLOWJEDEC A112A / J-STD-20-ACONV OVEN
  MAX. TEMP 220C

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• PACKAGE COPLANARITYJEDEC B108

• 20/20 Pass

• STABILIZATION BAKEJEDEC A103ATEMP 150C,
  200hrs.

• PHYSICAL DIMENSIONSJEDEC B100A

INC
INC
INC
INC
INC
INC

• TEMPERATURE CYCLINGJEDEC A104B, Condition B100
  CYCLES, 125C to -55C

INC
INC
INC
INC
INC
INC

• PRECONDITIONINGJEDEC A113B85C/85HR, 168hrs

• N 20

20/20Pass
INC
INC
INC
INC
INC

• WIRE BONDABILITY

• WIRE PULL STRENGTHMIL-STD-883E, Method 2011.7
  N 20

• MAX/MIN10.5g 8.5g12.1g 8.1g

• MAX/MINXX.Xg X.XgXX.Xg X.Xg

• MAX/MINXX.Xg X.XgXX.Xg X.Xg

• MAX/MINXX.Xg X.XgXX.Xg X.Xg

• MAX/MINXX.Xg X.XgXX.Xg X.Xg

• MAX/MINXX.Xg X.XgXX.Xg X.Xg

• DIE ATTACHABILITY

• INTERNAL VISUALMIL-STD-883E, Method 2010.10
  2017.7 N 20

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

• 20/20 Pass

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Eutectic Die Attach in an Air Cavity Plastic
Package !
The R-Pak low cost injection molded packaging
process combines the thermal advantages gained by
using a eutectic die attach material between die
and backplane with a moisture resistant plastic
sidewall specifically designed to manage higher
frequency and power.

• Features
• Eutectic Die attach
• Moisture resistant
• Low CTE
• CTE matched package
• Low Dielectric
• Low Parasitics
• High Power
• High Frequency
• Low Cost !

• Package Applications
• RF/ Microwave
• WLAN/ LAN
• Short Range Wireless
• MEMS/ MOEMS
• LDMOS
• CCD/ CMOS

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www.rjrpolymers.com